FIELD TEST

Minelab Usa - Eureka Gold
By Chris Gholson
From Page 44
August, 2004 issue of Lost Treasure

I rolled over in bed unable to sleep; the bright red numbers read 4:35 a.m.

To early to get up yet, so I'll just lay here and think for a while, I said to myself. My mind wandered. I thought of all the things I had to do that day and all the things I could be doing instead, like prospecting. I adjusted the blanket and glanced once more at the clock, it glowed 5:15 a.m. Forget this; I'm going detecting, so I decided to kick back the covers with my foot.

In less than 40 minutes I found myself bumping along the Black Canyon Highway the Polaris 500 loaded and my trustee Eureka Gold resting peacefully in the backseat. I was drawn to an area on the eastern flank of Arizona's Bradshaw Mountains, a spot where I had managed a handful of nuggets a year or so back with the GP Extreme. If I remember correctly, the ground mineralization was not incredibly severe and there was plenty of exposed bedrock - just the sort of place for a VLF workout. The Eureka is Minelab's finest gold machine for under $1?. It is similar to the earlier version, the XT18000, which also featured Automatic Ground Balancing and Adjustable Operating Frequency. However, refinements have been made, which include: target detection with pitch variation, better signal-to-noise ratio in the electronics, and a 10 elliptical Double D coil supplied as standard equipment. The control box can be mounted in a variety of positions, including: forward shaft mounting, rear shaft mounting, hip mounted, or chest mounted (carrying bag for the latter two is sold separately). Personally, I tend to prefer the rear shaft mount position as it reduces fatigue on the forearm and eliminates annoying cable snags on brush and tree branches. The unit is powered by a rechargeable 12V NiMH battery, which also includes an 110V mains charger. I arrived at the gully quickly enough and began my usual ritual, which usually (if I don't have the quad) goes something like this: double-check the battery, strap on snake-proof chaps, load up backpack with two water bottles, grab pick and finally lock the truck doorswalk awaythen come back a few moments later to make sure the truck doors are really locked (slight case of OCD)! The sun was starting its slow rise in the east flooding the cactus covered slopes with a brilliant orange light; the desert could not have looked more beautiful. This was a great time of day to be out detecting. It was still cool and there was very little air traffic so interference was at a minimum. The gully I was walking towards had never given up monster nuggets but the fractured schist bedrock-poking out along the sides was extremely inviting. I rotated the Volume control to the maximum position. The Eureka beeped back signaling all was working well. Next, I adjusted the Threshold to a reasonable hum. Then I grabbed hold of the Sensitivity Control and rotated it fully clockwise. This control is an important feature because it affects the strength of all signals including, metal targets, mineralzation and external interference. Setting this control is simple crank it up as much as possible! If the detector behaves erratically and you experience difficulty ground balancing then turn it down until things stabilize. Flipping the Balance switch into the Fast Track position, I pumped the coil gently over the surface until the groaning threshold smoothed out. In variable ground, Fast Track will re-balance more rapidly and therefore maintain a better balance. However, very weak signals could be eliminated if the coil is repeatedly swept over it. In lesser-mineralized areas, Slow Track will maintain a suitable balance without threat of tracking out a target. With the detector set in the 60kHz position I took off. One of the things I love most about the Eureka Gold is its ability to shift operating frequencies. With a simple flick of the switch, the user can select between 6.4kHz, 20kHz, or 60kHz. A nice touch of flexibility - bravo Minelab!

Generally speaking, lower frequencies (6.4kHz) are best suited for seeking large nuggets at depth, while higher frequencies (60kHz) are preferred for chasing smaller bits near the surface. The first 45 minutes were rather boring, not a single target to be found anywhere. Shortly thereafter I encountered a modest rocky waterfall. I got zilch down below, but once above it I quickly snatched a small bit of yellow metal lodged within the schist. Okay, things were looking better. A few feet from the waterfall's edge I spotted a pile of dead branches lying in the gully. I walked up to it and swung across the top. Was that a signal I just heard or am I starting to hallucinate under the Arizona sun? With the help of my Diamond Tip pick, I quickly cleared it away so that I was looking at nothing but gravel. If this was a signal it was incredibly faint. I suspiciously flipped the switch into the Boost position and swung the coil over the spot again. What a difference! From that moment on, the switch might as well have been super glued in place! The Signal switch provides three levels of audio response: Normal, Fine ands Boost. I have always favored strong audio; I like to hear what is going on. The Boost setting offers a greater deal of amplification and (from what I noticed) substantial gains in depth penetration. Targets that were barely audible in the Normal and Fine positions were crisp and defined in Boost. As I learned later, the drawbacks of running in this setting can be heard when venturing into heavily mineralized ground. It amplifies the good stuff (i.e. gold nuggets) but it also boosts the unwanted background noise making it difficult at times to differentiate between true metallic targets and spurious ground noises and it gets even worse in 60kHz! In these situations, switch into Normal and reduce Sensitivity. You might also try elevating the coil slightly. I didn't want to take the chance of balancing it out, so I toggled between Fast Track and the Fixed position. This locked the machine in place guarantying that the target would not be tracked out. Taking an inch or two off the top made a huge impact, there was definitely a target lurking below. At five inches I banged into the bedrock. This was it; nothing can get deeper than this. A few scratches with my fingernails revealed exactly what I was looking for. It stood out like a beacon against the rusty clay a shiny 1.5-gram nugget! Early retirement wasn't eminent but it put a big smile on my face! A thorough search of the 10-foot area, yielded another two nuggets, both smooth as silk indicating they had made quite a journey from the original source. Visions of gold pulled me further up the wash and through the desert brush when suddenly my ears where met with an all too familiar sound, an eerie sort of hum. That hum was none other than about 5? bees!!! They were gathering pollen from the tiny yellow flowers blooming on the Palo Verde trees. Almost all of the bees in central Arizona are now classified as Africanized, or Killer Bees, and when they attack they mean business! It is not uncommon for unlucky victims to receive several thousand stings, sometimes proving fatal. Mountain lions, spiders, crocodiles, I can deal with - but to hell with those bees! I tucked my courage into my back pocket and did an immediate 180! I meandered down to a stretch of the gully that I had never really hammered because of the rubbish. I was never sure why this spot had accumulated so many bullets while the rest of the gully was rather clean. Only thoughts are that the flash floods separated it out, or someone used this spot as a backdrop for target practicing. The Eureka is outfitted with a Discriminator, which aids the operator in distinguishing between ferrous and non-ferrous targets. When activated, a blanking of the audio threshold alerts the operator that the coil has been passed over a ferrous object. In this case the discriminator would be of little help for wading through the lead. Even so, unless I am coin or relic hunting, I do not use discriminators. Unlike coins, nuggets vary greatly in both size and shape. They are also found at a wide range of depths usually in the nastiest iron-saturated soils on earth. Rather than gamble, I opt for the All Metal mode and try to dig as many targets as humanly possible. If you do decide to run with discrimination know this, it has difficulty processing large targets near the surface. I would suggest investigating these signals, especially when working known patches. In either case, the bottom end was a dry run. I was more than satisfied with the four smooth nuggets in my jar and happily hiked my way back to the quad, giving those Palo Verde trees plenty of breathing room! I'd be back but next time in body armor!

Conclusion

I was impressed with the overall performance of the Eureka. Actually I would rank it among the top 2 or 3 VLF machines on the market today. The low weight (2.2kg) and excellent design are a definite bonus. The controls are user friendly and the instruction manual is well written so there is no guesswork here. Adjustable operating frequencies, variable ground tracking speeds and the plethora of control box mounting positions were all major selling points for this nugget hunter. My only complaints in the performance department were the stability over black sands, certain varieties of clay and of course, the always-pleasant volcanic basalt. However, in all fairness, these are problems inherent to all VLF machines not just the Eureka. I might as well go ahead and gripe about the lack of headphones and the incredibly limited selection of search coils too. A 15 Spider DD coil can be purchased separately, but come on guys. I'd like to see some mid-sized coils possibly round and how about a monoloop coil wouldn't that be a dandy!

As I mentioned above, this machine scored well with me. I would place the Eureka at the top of the mid-range class. It offers great performance at a reasonable price. So, if you're looking for a maneuverable, lightweight, highly sensitive metal detector that will do damage to nuggets wedged in the bedrock, but not your wallet; the Eureka Gold is probably your baby! For more information on this and other Minelab products, please visit their website at www.minelab.com, or by calling 1-888-517-2066. Additional information on electronic prospecting can be found on the author's website at www.arizonaoutback.com. See you on the goldfields!



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